Automatic traffic control for conveyers



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W. BISSET June 29, 1954 AUTOMATIC TRAFFIC CONTROL FOR CONVEYERS Filed May 7, 1951 June 29, 1954 w, 515,551- 2,682,329

AUTOMATIC TRAFFIC CONTROL FOR CONVEYERS Filed May 7, 1951 FIG. 2. 22

2 Sheets-Sheet 2 5313 )AT TORNEY Patented June 29, 1954 UNITED STATES OFFICE AUTOMATIC TRAFFIC CONTROL FOR GONVEYERS Application May 7, 1951, Serial No. 224,881

7 Claims. 1

This invention relates to automatic trafiic control devices for conveyors and is an improvement upon the automatic tramc control disclosed in U. S. Patent No. 2,130,330, granted September 13, 1938, upon an application filed March 9, 1938, by Gerald J. Sibley, and assigned to the same a signee as this application.

As illustrated in the above-mentioned patent, the purpose of this type of conveyor traflic control is to control the movement of articles along adjacent conveyors so passage of articles on one conveyor is interrupted during passage of an article on the other conveyer. Usually, these traffic control devices are used to prevent collision of articles being fed from two conveyers onto a single conveyer.

The traffic control is accomplished by a pair of control arms, one arm overlying each of the conveyors. These arms assume article blocking positions overlying their respective conveyors and are moved by the passage of articles away from their blocking positions. Interlocking devices lock one arm in blocking position upon movement of the other arm away from blocking position. These interlocking devices include locking elements movable with the respective arms and arcuate projections also movable with the respective arms, the arcuate projections moving into the paths of the locking elements upon displacement of their respective arms from blocking position.

While traffic control devices like the one shown in the above-mentioned patent have worked satisfactorily in most cases, there have been instances where pressure on an arm in blocking position tends to jam the mechanism with the other arm displaced from blocking position. An increase in spring tension or weight for returning an arm to blocking position does not satisfactorily solve the problem because, in the absence of some retarding force, a control arm may be returned to blocking position so rapidly it will damage on-coming article. To avoid jamming, it has been necessary to use precision bearings for the control arms in the patented devices so the arcuate projections would at all times present truly arcuate surfaces for engagement by a looking element and hence would not jam the mechanism. Even so, there are instances where the control arms return to blocking positions very slowly thereby slowing down the movement of articles along the conveyers.

A major object of this invention is to provide an automatic traffic control for conveyors, which traffic control is not subject. to jamming due to pressure of an article on a control arm in blocking position. Another object of the invention is to utilize the pressure of an article on a control arm in article blocking position to facilitate the return of the other control arm to article blocking position and thereby reduce the period during which an article is blocked so the speed of travel of articles along the conveyors is not materially affected.

In accordance with these objects, an important feature of the invention resides in the arrangement, on the arcuate'projection of a cam surface in such a manner that pressure exerted by the locking element of a control arm in' blocking position on the cam surface tends to return the other control arm in blocking position. With this feature, the conveyor trafiic control may be manufactured with relatively inexpensive loose type ball bearings. This reduces the overall cost of the unit and increases the efficiency of the traffic control by expediting the return of a control arm when pressure is applied to the other control arm in its blocking position.

ther objects and advantages of the invention will become apparent from the following specincation taken in conjunction with the accompanying drawings wherein:

Figure 1 is a fragmentary top plan view showing the preferred form of the invention as applied to a pair or intersecting conveyers;

Fig. 2 is a vertical sectional view taken on the line Z--2 of Fig. 1;

Fig. 3 is a horizontal sectional view taken on the line :i3 of Fig. 2; and

Fig. 4 is a vertical sectional view taken on the line 4- 2 of Fig. 2.

In the embodiment illustrated in Fig. 1, a belt conveyor I I is intersected by a roller conveyor I2, one side rail [3 of conveyor ii intersecting a side rail It or conveyer 12 at a point it, and forming an acute angle between the side rails of the two conveyors. The conveyer traffic control, for preventing collision of articles from the two conveyers at the point of intersection, has a box-like frame It formed with a top I; and a bottom Iii, connected by back wall it, and a front post 2i. Side edges 2!? and 23 of top Ii, and side edges 24 and 25 of bottom it, converge at the same acute angle as side rails l3 and id of the two conveyors, so the traffic control frame may be supported between the two conveyors by brackets .25 and 2'! secured as by a welding to bottom it, and fastened by bolts 28 and '29 to side rails 93 and M, respectively.

At one side of the frame, a rod 3! extends from top H through bottom 18 where it is secured by a nut 32. A vertical roller 33 is rotatably supported by bearings 34 and 35 on the rod 3|. Secured to roller 33 by a bracket 31, and extending radially from the roller, is a control arm 36 projecting through the open side of the frame l6 over the conveyer Normally urging roller 33 and arm 36 in a counter-clockwise direction, as viewed in Fig. 1, is a weight 38 connected to the roller 33 by a flexible cord 39, extending over pulley 4|. Cord 39 surrounds roller 33 between bracket 31 and a collar 40 clamped on the roller below the bracket. A stop, in the form of a bolt 42, is secured by nuts 43, 43, to the back of the frame adjacent the side rail |3 of the conveyer This stop 42 is arranged to engage upwardly extending flange -44 of the arm 36 and retains the control arm in article blocking position as shown in the drawings. In this article blocking position, control arm 35 overlies the conveyer I and extends transversely across the conveyer so it will be engaged by any article moving along the conveyer toward the intersection of the two conveyers.

On the opposite side of the frame |6, a similar rod 45 is secured by nut 41 at the bottom l8 and has bearings 48 and 49 rotatably supporting vertical roller on the rod 46. Another control arm 52 is supported on roller 5| by a bracket 53. Control arm 52 extends radially from roller 5| through the open side of the frame l6 to an article blocking position overlyingthe conveyer l2. Weight 54 is connected to roller 5| by flexible cord 55, extending over pulley 55. Cord 55 surrounds roller 5| between bracket 53 and a collar 51 clamped on the roller, so that weight 54 normally urges control arm 52 toward blocking position overlying conveyer I2 and extending in a direction transversely of the conveyer. In this blocking position, vertical flange 58 is engaged by stop 59 secured by nuts 6!, 6|, to back IQ of the frame adjacent side rail IA of conveyer l2.

For the purpose of locking one control arm in blocking position when the other arm is displaced from blocking position, interlocking devices are provided for the control arms. These interlocking devices include a locking arm 63 mounted on collar 40 clamped on roller 33 and movable with arm about the axis of pivot rod 3|. Also supported for movement with the control arm 36 is a locking element in the form of a roller 65, rotatably mounted on a stub shaft 66 extending upwardly from locking cam 63. For purposes to be explained, roller 65 is positioned at the end cam 63 which is remote from the control arm 36.

Movable with control arm 32 and mounted on collar 51 clamped on roller 5| is a second locking cam 61 which has a locking element in the form of a roller 53 rotatably mounted on stub shaft 69 extending downwardly from the bottom of locking cam 61 at the end of the locking cam remote from the control arm 52. Locking cams 63 and 61 are vertically displaced so they do not interfere with each other.

When control arm 36 is moved about the axis of rod 3|, locking element 65 moves in an arcuate path about the same axis. Similarly, locking roller 68 moves in an arcuate path with arm 52 about the axis of rod 46. In Fig. 1, control arm 36 is shown in its blocking position. When it is moved from blocking position, locking cam 63 moves into the path of movement of locking roller 68 so movement of control arm 52 from its article blocking position is prevented by engagement of roller 68 with cam surface 1| on the locking cam 63. Similarly, displacement of control arm 52 from its article blocking position moves locking cam 61 into the path of locking roller 65 thereby preventing displacement of control arm 36 from its article blocking position by engagement of locking roller 55 with cam surface 12 on cam 61. Thus, articles can pass the traffic control along only one conveyor at a time. As an article passes along one conveyer, the control arm across the other conveyer is locked in article blocking position.

Cam surfaces 1| and 12 are asymmetrical with respect to axes A and B about which turn the control arms 36 and 52 with their associated elements. The radial distances of the respective cam surfaces from these pivotal axes increase in directions away from the locking elements on the other arms and decrease in directions toward the points of initial engagement of the cam surfaces with the respective locking elements. Thus, the radial distance of cam surface 1| from axis A increases in a direction away from blocking element G8 and decreases in a direction toward the point of initial engagement of cam surface 1| with locking element 68. Similarly, the radial distance of cam surface 12 from pivotal axis B increases in a direction away from locking element 65 and decreases in a direction toward the point of initial engagement of the cam surface 12 with the locking element 65. In its preferred form, this arrangement of the cam surfaces is accomplished by providing cam surfaces of arcuate formation, the centers of the arcuate cam surfaces being offset from the pivotal axes A and B in directions toward the respective control arms 36 and 52. Thus, cam surface 1| is of arcuate formation with the arc of the cam surface having a center C offset from axis A in a direction toward control arm 36. Similarly, arcuate cam surface 12 has its center D offset from pivotal axis B in the direction of control arm 52.

With these cam surfaces asymmetrically arranged relative to their respective pivotal axes, pressure of a control arm in article blocking position acts through its locking element on the asymmetrical cam surface for the other control arm in a manner tending to force the other control arm to return to its blocking position. For example, assuming control arm 52 is displaced from its article blocking position by the passage of an article along conveyer l2 and an article on conveyer II is pressing on control arm 36 in its article blocking position, the pressure exerted by the article will be transmitted to locking roller 65 which will be engaged with the cam surface 12 of locking cam 61 for control arm 52. Due to the asymmetrical arrangement of the cam surface 12 with respect to pivotal axis B, the pressure applied by roller 65 to the cam surface 12 will tend to move cam 61 in a clockwise direction, as illustrated in Fig. 1, and thereby force control arm 52 toward its article blocking position. Thus the force of weight 54 tending to return control arm 52 to blocking position is augmented by a force resulting from pressure of an article on control arm 36. In the same way, if control arm 36 is displaced from its article blocking position, pressure of an article on control arm 52, while in its article blocking position, is transmitted through roller 68 onto cam surface 1| thereby applying a force tending to turn cam 63 in a counter-clockwise direction, as viewed in Fig. 1, and thereby increase the force exerted by weight 38 urging control arm 36 to return to its article blocking position.

From the foregoing description, it will be apparent that the pressure of a blocked article on the control arm in blocking position is utilized to expedite the return of the other control arm to its blocking position whereas the traffic control shown in the above-mentioned patent had' its speed of operation reduced by the pressure of an article on the control arm. Instead of retarding the operation of a trafiic control device constructed according to the present invention, pressure of an article on a control arm in article blocking position expedites the return of the other arm and thereby reduces the time during which an article is blocked. Because the pressure of an article on a control arm in article blocking position aids the return of the other control arm toward article blocking position, difliculties heretofore solved only through use of precision bearings have been eliminated so a traffic control device made according to this invention is less expensive to manufacture and performs more satisfactorily.

What is claimed is:

l. A conveyer trafiic control comprising a frame, a pair of control arms pivoted on said frame, said control arms being independently movable to and from blocking positions respectively overlying separate conveyers, a locking element on one of said arms and movable therewith, a blocking element moved into the path of said locking element upon movement of said other arm from blocking position to engage said locking element and prevent movement of said one arm from blocking position, and means on said blocking element actuated by pressure of said locking element in response to pressure on said one arm urging said other arm toward blocking position.

2. A conveyer traffic control for controlling the passage of articles over two separate conveyer lines, said conveyer traffic control comprising a pair of arms, one arm adapted to normally project over one conveyer and the other arm adapted to normally project over the other conveyer in the path of articles traveling along said conveyers, said arms each being pivotally mounted to swing from article blocking position to a position permitting articles to pass, interengaging blocking elements actuated by movement of said arms whereby pivotal movement of one arm locks the other arm in article blocking position, and means on said elements actuated by pressure on either arm in blocking position responsive to pressure of an article for forcing toward blocking position the other arm.

3. A conveyer traffic control comprising a frame, a pair of control arms pivoted on said frame for independent movement relative to a pair of conveyers, means urging each of said arms toward a blocking position overlying its respective conveyer, a locking element on each of said arms movable therewith, a blocking element on each of said arms moved into the path of the corresponding locking element upon movement of either arm from blocking position, and means on both said blocking elements actuated by pressure of said locking elements in response to pressure on either arm in blocking position for increasing the force urging the arms toward blocking positions.

4. In a conveyer traffic control having a frame, a pair of control arms pivoted on said frame, said control arm-s being independently movable to and from blocking positions respectively overlying separate conveyers, an interlocking device for said arms comprising a locking element on one arm and movable therewith in an arcuate path, and a locking cam movable with the other arm, said cam being movable into the path of said element upon movement of said other arm from its blocking position and having a cam surface engageable by said element, said cam surface being asymmetrical relative to the pivot for said other arm so pressure on said one arm acts through said element and said cam to urge said other arm toward its blocking position.

5. In a conveyer traffic control having a frame and a pair of control arms pivoted on the frame for independent movement to and from blocking positions respectively overlying separate con-- veyers, an interlocking device for said arms comprising a pair of locking elements, one element being movable with each of said arms, locking cams, one cam on each arm movable into the path of the element on the other arm upon movement of each arm from its blocking position, said cams having surfaces of increasing radius from the axis of the respective pivots in directions away from the locking elements on the other arms so pressure on an arm in blocking position forces the locking element on that arm against the cam surface on the other arm to urge said other arm toward blocking position.

6. In a conveyer traffic control having a frame and a pair of control arms pivoted on said frame for independent movement to and from blocking positions respectively overlying separate conveyers, an interlocking device comprising a first locking element movable with one arm, a second locking element movable with the other arm, a first locking cam movable into the path of said second element upon movement of said one arm from blocking position, a second locking cam movable into the path of said first element upon movement of said other arm from its blocking position, and cam surfaces on both of said looking cams for engaging the respective elements, the radial distances of said surfaces from the respective pivots decreasing toward the points of initial contact of said surfaces with the respective locking elements.

7. In a conveyer trafiic control having a frame and a pair of control arms pivoted on said frame for independent movement to and from blocking positions respectively overlying separate conveyers, an interlocking device comprising a first locking element movable with one arm, a second locking element movable with the other arm, a first locking cam movable into the path of said second element upon movement of said one arm from blocking position, a second locking cam movable into the path of said first element upon movement of said other arm from its blocking position, and cam surfaces on both of said locking cams for engaging the respective elements, said cam surfaces being of arcuate formation with the centers of the arcs offset from the axes of the respective pivots in directions toward the arms with which said cams are movable in a manner such that pressure on one arm acts through its element and the cam surface engaged thereby to force the other arm toward blocking position.

References Cited in the file of this patent UNITED STATES PATENTS Number 

